Mix all prepared vegetables in a large serving bowl. In another medium bowl, flake tuna by means of a fork or by hand. Add tuna to vegetables and mix by means of two salad servers. Mix in capers and black olives. Into a screw top glass jar; add all dressing ingredients. Go slow on salt; adding it to taste. Close tightly and shake vigorously until all ingredients are incorporated and thickened. Drizzle dressing on salad mixture. Mix well with servers. Sprinkle crumbled feta cheese all around the top; alternating with the egg quarters. Serve with crusted bread; as a lunch meal of its own, or as a starter for a fish or a seafood dish.